13927-98-5Relevant academic research and scientific papers
Co-ordination Chemistry of Higher Oxidation States. Part 38. Synthesis, Spectroscopic and Electrochemical Studies of some trans-Dihalogenoosmium Complexes. Crystal Structure of trans-BF4
Champness, Neil R.,Levason, William,Moulxd, Roy A. S.,Pletcher, Derek,Webster, Michael
, p. 2777 - 2784 (1991)
The complexes trans- (X = Cl or Br) have been obtained from and PMe3, and trans- by reduction of appropriate osmium(III) complexes in the presence of L.The complexes cis- are formed by isomerisation of the trans analogues in chlorinated solvents, and in other ways.Air oxidation of the osmium(II) complexes gives trans-BF4 (L = PMe3 or AsMe3), but formation of trans-BF4 (L = PMe2Ph, SbPh3 or py) and cis-BF4 requires HNO3 as oxidant.Use of concentrated HNO3 gives trans-(2+) (L = PMe3, PMe2Ph or AsMe3) in solution, but these have not been isolated.The complexes have been characterised by IR, UV-VIS, and NMR spectroscopies, and the effect of stereochemistry and L and X upon the OsII-OsIII and OsIII-OsIV redox potentials probed by cyclic voltammetry.The crystal structure of trans-BF4 has been determined: orthorhombic, space group Fddd, a = 8.104(4), b = 32.195(11), c = 38.540(9) Angstroem, and Z = 16.The cation has Os-P 2.419(5) and 2.398(5) Angstroem and Os-Cl 2.352(4) Angstroem, and shows deviations of the OsP4 unit from planarity due to steric interactions.There is no evidence that mer- (L = PEtPh2, AsMe2Ph, SbPh3 or SMe2) can be oxidised either chemically or electrochemically to stable iridium(IV) cations.
